Stormwater Guidance Manual

1 Stormwater Manual : A GUIDE TO Stormwater REQUIREMENTS FOR LAND DISTURBING ACTIVITIES IN ARLINGTON COUNTY July 2021 i July 2021 1 Introduction .. 1 2 Stormwater Pollution Prevention plan (SWPPP) Requirements .. 2 Erosion and Sediment (E&S) Control plan .. 2 Stormwater management plan (SWMP) .. 2 Contents of plan .. 2 Water Quantity Technical Criteria .. 5 Water Quality Technical Pollution Prevention plan (P2 plan ) ..33 Registration Statement Stormwater Facility Maintenance and Monitoring Agreement (MMA).

2 34 Construction Operator Inspections ..34 Construction Record Drawing Requirements (As-built Certification) ..34 Enforcement ..34 Requirements for Single Family Residences Built Separately ..34 Additional performance requirements effective September 13, 2021 ..35 Alternative Compliance Option ..38 Streamlined Method ..41 Fee Schedule ..43 Bonds ..44 Post Construction Inspection and Maintenance 3 Landscape Conservation plan Requirements ..45 plan Requirements for Site plan and Other Conditioned Projects.

3 46 plan Requirements ..46 Landscape Conservation plan ..46 Tree Protection plan ..47 Tree Planting/Landscape plan ..50 Details and Correspondence ..52 Requirements Before and During Construction ..52 Violations and Mitigation ..53 Exemptions ..53 4 Resource Protection Area Requirements ..54 Resource Protection Area ..54 Flow Chart for Resource Protection Area Compliance ..55 Subdivision Plats ..56 plan Requirements for Projects Disturbing 2,500 square feet ..56 ii July 2021 RPA Delineation.

4 56 Water Quality Impact Assessments ..57 Exceptions ..59 What Activities in the RPA Require an Exception? ..59 Exception Requests Process ..60 RPA Mitigation and Buffer Enhancement Requirements ..60 Mitigation and Buffer Enhancement Guidance for single family home projects ..61 Re-vegetation and Buffer Enhancement plan Elements ..62 Projects Disturbing Less Than 2,500 Square Feet in the RPA ..64 Mitigation and Buffer Enhancement ..65 Buffer Modification and Discrete Tree Removal ..65 Exempted Activities.

5 66 5 Floodplain Requirements ..66 Appendix A: Stormwater Facility Maintenance and Monitoring Agreement (MMA) Appendix B: SWPPP Template Appendix C: Water Quality Impact Assessment Data Sheet Appendix D: Exception Request Form Appendix E: 20-Yr Tree Canopy Coverage Worksheet Appendix F: Tree Protection and Planting Standards Appendix G: Construction Inspection Checklists and Certification Templates Abbreviations Chapter 57 Erosion and Sediment Control Ordinance Chapter 60 Stormwater management Ordinance Chapter 61- Chesapeake Bay Preservation Ordinance CO Certificate of Occupancy DES Arlington County Department of Environmental Services Director - Director of the Department of Environmental Services or designee.

6 DEQ Virginia Department of Environmental Quality ISD Arlington County Inspection Services Division LDA Land Disturbing Activities Permit iii July 2021 MMA - Maintenance and Monitoring Agreement RPA Resource Protection Area SWMF Stormwater management Facility VRRM Virginia Runoff Reduction Method WQIA Water Quality Impact Assessment 1 July 2021 1 Introduction This Manual outlines the Stormwater requirements for all land disturbing activities in Arlington. A Land Disturbing Activity/ Stormwater (LDA) Permit is required for any land disturbing activities that disturb equal to or greater than 2,500 square feet of land, as required by the Erosion and Sediment Control Ordinance (Chapter 57), Stormwater management Ordinance (Chapter 60), and the Virginia Erosion and Sediment Control Program.

7 Land disturbing activities within Resource Protection Areas (RPAs) regulated under Chesapeake Bay Preservation Ordinance (Chapter 61) are also governed by this Manual . The term Director in this Manual refers to the Director of the Department of Environmental Services (DES) or designee. The area of land disturbance includes cumulative land disturbance over two (2) years, which will be calculated for any project during this period that involves structures, paved areas, and/or retaining walls to track whether the cumulative threshold is exceeded.

8 Projects with land disturbance of 2500 square feet or greater are subject to the requirements of Chapter 2 and 3 of this Manual . Any land disturbance in a Resource Protection Area (RPA) is subject to the requirements of Chapter 4 of this Manual . The following flowchart outlines the submission process for activities that will cause land disturbance. 2 July 2021 2 Stormwater Pollution Prevention plan (SWPPP) Requirements Any activity that disturbs 2500 square feet or more of land requires a Stormwater Pollution Prevention plan per the requirements of Arlington County Code Chapter 60.

9 This plan contains the fol lowing elements: Erosion and Sediment (E&S) Control plan Stormwater management plan (SWMP) Pollution Prevention plan (P2 plan ) Virginia Stormwater management Program (VSMP) Requirements Stormwater Facility Maintenance and Monitoring Agreement (MMA) Erosion and Sediment (E&S) Control plan An erosion and sediment control plan must be submitted that satisfies the requirements of Arlington County's Erosion and Sediment Control Ordinance (Chapter 57 of the County Code). Specifically, the E&S plan must: Minimize the construction footprint.

10 Delineate the limits of clearing and grading, including details about how these limits will be physically marked in the field. Delineate the RPA boundary (see Chapter 4 of this Manual ), including details about how this boundary will be physically marked in the field. Include tree protection measures required under the approved Landscape Conservation plan to ensure protection during clearing, grading, and all phases of construction. Provide for a single ingress/egress point for construction activities, unless otherwise approved by the County Manager.